The present invention relates to an image-forming material excellent in various performances such as sensitivity, resolution and quality of images formed and having various uses and a method for forming images using the image-forming material which is superior in operability and productivity. More particularly, it relates to a material which is very high in sensitivity, can be exposed with air-cooled argon laser beam, helium-neon laser beam or semiconductor laser beam and can form good resist images and a method for forming the resist images. Furthermore, it relates to production of a printed wiring board, formation of metallic masking images, production of name plates, minute working of metals and making of printing plates.
Silver halide gelatin emulsion photosensitive systems are generally high in sensitivity and resolution and excellent in consistency and storage stability. Therefore, the systems have hitherto been widely used in the fields of general photographic field, medical field and photomechanical field. However, a few of them have been used as a means for forming resists.
As mentioned above, the systems have many merits and if the formation of resists using the silver halide photosensitive systems can be advantageously attained, the systems can be widely applied. For example, they can be applied to minute working of metallic semiconductors and insulators and patterning of inorganic or organic thin films and especially they can be applied to the fields of working of materials relating to electronics and production of name plates and in addition, various art workings and printings.
Particularly, the techniques of designing and graphics using computer design CAD/CAM have recently made rapid progresses and the graphics technique using scanning output from lasers and LED arrays have already been put to practical use in various fields. There have been desired resist-forming materials high in sensitivity and high in quality of images formed which are adaptable to direct scanning exposure, especially laser scanning exposure and moreover, low energy laser beams such as air-cooled argon laser beam, helium-neon laser beam and semiconductor laser beam which are advantageous in cost and stable and a method for forming the resists has also been desired. The enhancement of sensitivity in the field of resist has also been desired in the field of general resists ("J. Soc. Photogr. Sci. Technol. Japan", Vol. 54, P684 (1991)). However, at present the sensitivity corresponding to 100 .mu.J/cm.sup.2 is the limit and there are problems in storage stability and image quality.
As examples of application of silver halide photosensitive systems, though they are not necessarily examples of resists, British Patent Nos.1,571,155 and 1,567,844 and U.S. Pat. No. 4,168,167 disclose photosensitive lithogrpahic printing plates comprising an aluminum support and a photosensitive silver halide emulsion layer directly provided on the support. However, these photosensitive lithographic printing plates have the problems such as occurrence of fogs and spots.
Furthermore, as examples of improvement of one of the problems, U.S. Pat. Nos. 4,268,609, 4,347,305 and 4,358,530 propose photosensitive lithographic printing plates which comprise an aluminum support and a photosensitive silver halide emulsion layer between which a non-silver photosensitive layer is provided. The non-silver photosensitive layer comprises (1) a diazo resin, (2) an o-quinonediazide, (3) a photosensitive azide compound, (4) a polymer compound containing --CH=CH--CO--group in the main chain or the side chain, (5) an addition polymerizable unsaturated compound, a photopolymerization initiator and a polymer compound as a binder or the like.
Furthermore, L. Plambeck et al proposed to make a printing plate by forming relief images by selective washing-off after exposure and development with use of a bifunctional color developing agent and a polymer coupler (J. Image. Sci., 30, 221 (1986)).
For example, in the field of printed wiring board, the screen printing process and the photographic process which use a liquid resist or a dry film resist are used for formation of resist images. With recent demand for enhancing performances of printed circuit boards, enhancement of sensitivity of photoresist or dry film resist has been studied (e.g., J. Soc. Photogr. Sci. Technol. Japan, Vol. 54, P684 (1991) and Application of New Photofunctional Polymer, CMC (1988)). However, sensitivity and resolution of the printed wiring boards produced using them are generally low and besides, the production steps are complicated. Therefore, many operational steps and much time are required for production of printed wiring boards.
Japanese Patent Kokai No. 63-129689 proposes a method for making printed wiring boards improved in these problems. That is, this method comprises directly drawing a circuit pattern on an organic photoconductive layer by laser beams, forming a toner image by electro-photographic process and making a printed wiring board using the toner image as the resist.
However, for making the above-mentioned photosensitive printing plate comprising a support and a photosensitive silver halide emulsion layer between which a non-silver photosensitive layer is provided (U.S. Pat. No. 4,268,605), an exposure to ultraviolet rays for exposing the non-silver photosensitive layer is required subsequent to the first exposure, development and fixation and thus, there are problems such as complicated systems of equipment and steps and deterioration of resolution owing to the low sensitivity of the non-silver photosensitive layer and owing to using a light source which lacks parallel properties.
Furthermore, the above-mentioned method comprising production of resist images by electro-photographic process (Japanese Patent Kokai No. 63-129689) have the following problems. That is, (a) charging of the organic photoconductive layer is necessary just before exposure and a special device must be provided, (b) the characteristics of the organic photoconductive layer depend greatly upon environmental conditions such as temperature and humidity, and (c) the organic photoconductive layer is apt to adsorb dusts, and spots are liable to be produced.
Moreover, according to the method of crosslinking of the polymer couplers with the oxide of the color developing agents, resolution lowers due to the diffusion of the oxide.